At Saab, we constantly look ahead and push boundaries for what is considered technically possible. We collaborate with colleagues around the world who all share our challenge – to make the world a safer place.

Business unit Airborne Surveillance System is responsible for airborne radar systems and you will be part of the section Concepts & Functions responsible for advanced system studies related to current and future products.

Your role

Estimating the frequency, amplitude and damping parameters of sinusoidal signals from noisy measurements is an important part in many applications, and one example is here radar applications. Because of its many applications the problem has been extensively investigated in the past. To determine the unknown parameters by a direct minimization of a quadratic data term leads to a non-convex problem which is difficult to solve using non-linear programming methods when the number of sinusoidal components is large.

If the measurements are formed into a Hankel matrix, then in the ideal noise free case, the rank of the Hankel matrix will correspond to the underlying system order and properties in the Hankel structure can be used to directly calculate the sinusoidal signal parameters without non-linear programming. Therefore, the problem can instead be formulated as a least-squares optimization problem to find a Hankel matrix which approximates the matrix of measurement that has a pre-determined rank. This kind of optimization problems can be solved in multiple ways and new methods has recently been introduced in the literature.

Objective:

The thesis will:

Evaluate different formulations of the optimization problem and how it affects the accuracy of the estimation.

Compare optimization solvers in terms of robustness and computational properties.

Investigate how well the proposed methods handle special cases such as missing measurement values, e.g. the missing data case

Present the result in a report and with a presentation.

Your skills and experience

The thesis is suitable for one or two students with relevant background.

The position entails working with classified information. Therefore, you are required to participate in and pass a security test conducted by authority.

Saab is a global defence and security company operating in the fields of air, land and naval defence, civil security and commercial aeronautics. We number 15,500 employees and have operations on all continents. Technologically we are leaders in many areas, and one-fifth of our earnings are spent on research and development.

Saab is also a company with opportunities. A company where we see diversity as an asset and where you have both considerable responsibility and good opportunities for advancing in your career. But also a company that respects each person’s needs for a rewarding life beyond work.